Classification is the orderly, systematic arrangement of related things in accordance with a governing principle or basis. The classifier notes the structural and functional relationships among things that constitute a class. In recording this relationships, the classifier employs certain conventional terms. Acquaintance with these convenient terms will make the rest easy to follow.

Genus and Species

A genus is a class; a species is a subdivision within a class. If technical subjects are the genus, then, TC, Chemistry, and Calculus are species; if calculus is the genus, then differential, integral, and infinitesimal are species. These two terms are very commonly used, but many others can be used if a more complex classification is needed.
The animal life gives as much as 21 categories from subspecies, species, subgenus, genus, subtribe, tribe, subfamily, family, superfamily, infraorder, suborder, order, superorder, chort, infraclass, subclass, class, superclass, subphylum, phylum, and finally kingdom, the broadest group of all. Elaborate classifications are designed to tell all that is known about the structural and functional relationships among the individuals of the classification.

Classification

This term has a loose popular meaning and a more precise technical one. Popularly, classification is almost any act of noting relationships. Technically, classification is the act of locating a specimen of all the different kinds of objects that posses a given characteristic or characteristics. Initially, classification must begin with the recognition that different things posses similar characteristics.

Logical Division

The division of the collected data which is already classified is called logical division. In report writing it is usually logical division, not classification that is concerned with; nevertheless, the term “classification” is the one most likely used even where “logical division” is technically correct.
One might write, “Engines can in general be classified as full diesel, modified diesel, and gas.” This is logical division simply because it is a division into three groups of information already known. But it is likely that an engineer or a technician would say “classified” rather than “logically divided” – to judge from our own acquaintance of technical literature. For that reason and for convenience in general, the term “classification” to mean either logical division or classification is used. The chief concern will focus in logical division, since the report writer is almost concerned with arranging a collection of facts or ideas, in order to discuss them in return, rather than hunting down new species. After all, the hunting will necessarily have been done before the writing starts.
If we are going to use the term “classification” you may wonder why we bothered to distinguish between it and logical division at all. The reason is twofold: first, just to get down all the facts; and second, to avoid confusion when we go to the next term on our list.

Partition

Partitioning is the act of dividing a unit into its components. The parts do not have necessarily had anything in common beyond the fact that they belong to the same unit. A hammer may be partitioned into head and handle. Hammers may be logically divided according to physical characteristics of their heads as claw, ball peen, and so forth. Classification, or logical division, always deals with several (at least two) units. Partition deals with the parts of only one unit. A hammer is a single unit. A hammer head without a handle is not a hammer. The head and the handle are parts of a single unit. You have probably become familiar with a variety of partitioning in a chemistry course when you determine the components of a chemical compound.

Basis

At the beginning of this subject we have classified engines. How should we classify engines? On the bais of power, use, the kind of fuel they burn, or where the combustion occurs? The manufacturer who is looking for a gas engine to use in a power lawn mower scheduled for production would not thank you for a classification of small engines according to the place where the combustion occurs. What basis would be helpful? Power? Weight? Cost?
These terms, then, are the ones to remember; genus and species, classification, logical division, partition, and basis.

When is Classification a useful expository Technique?

The foregoing discussion has suggested why classification is a useful technique of exposition: it permits a clear, systematic presentation of facts. When to use this technique depends on whether a writer is dealing with classifiable subject matter and whether his or her writing can be made more effective by means of the technique.
To get an idea of when this technique is useful, let’s consider a specific writing problem. Let’s suppose that a report is needed on kinds of vat dyes (capacitors for elex, wires for electrical, drill bit for mech). And let’s suppose further that the readers of this report will need to be given an understanding of the properties of these dyes so they can use the dyes effectively. It would be possible to discuss each of the 40 or 50 dyes in turn, of course, giving all the pertinent information about dye No. 1, dye No. 2, and so forth. But it is hard for any reader to keep in mind 40 or 50 individual sets of characteristics. A better possibility is to classify all these dyes into groups having characteristics in common. It would be much easier for readers of the report about these dyes to remember the characteristics of a group, and to relate an individual dye to a group, that it would be to memorize the behavior of all the dyes individually.
Classification, then, is useful when you have a number of like things to discuss, among which there are points of similarity and difference which is important for the reader to understand. Obviously, however, the relationship among the things classified must be a significant one.
Suggestions to follow in presenting a classification in using classification as an effective way of presenting related facts, it is helpful to follow a number of “rules,” all of which are simply commonsense suggestions for clarity and meaningfulness.

1. Make clear what is being classified. This needs the definition of the subject if there is a question as to whether the reader will be familiar with it. Grouping the related members of a class will mean little to a reader who does not know what you are talking about in the first place.

2. Choose (and state) a significant, useful basis, or guiding principle, for the classification. The basis of classification governs the groupings of members of a class. A classification of drafting pencils according to the color they are painted would be of no value at all, perhaps to the aesthete who prefers a magenta to a pink. The bais should point to a fundamental distinction among the members of a class.

3. Limit yourself to one basis at a time in listing members of a class. Improper choice of terms is not so obvious an error in this area of concern. An author, illogically listing fuels as “solid, gaseous, and automotive,” may actually have been thinking correctly of “solid, gaseous, and liquid,” but no matter what this author was thinking, the term “automotive” was illogical. Still another practice to avoid is the listing of a specific variety instead of a proper species name, as listing fuels as gas, liquid, and coal (instead of “solid”).

Name all species according to a given basis. Tell the readers what the limitations are upon the classification you are presenting, so that they will not expect more that it is your intention to give. Classification of steels according to method of manufacture, for instance, would not need to contain mention of obsolete methods. Limiting a classification means making clear what is being classified and for what purpose. Thus, a classification of steels might begin: “Steels commonly in use today in the Philippines are made by . . . ” The rest of the statement would name the methods of production. In this statement three limitations are made: steels made by uncommon methods of production are neglected, steels made by the methods of the past are omitted, and finally steels made in other parts of the world are ignored.

Make sure that each species is separate and distinct – that there is no overlapping. The species of a classification must be mutually exclusive. Classification of reports as research, information, investigation, recommendation, and so on illustrates this error, for it is obvious that not one of these necessarily excludes the others; that is, a research report may most certainly be an investigation report or a recommendation report. To guard against this error, examine the listing of species you have made and ask yourself whether species A can be substituted for species B or C, or for any part of B or C.

Help your reader understand the distinction between species. Discuss each species, giving a definition, description, or illustration of each – perhaps all three. In a discussion of steels it might be desirable, according to a basis of the number of alloy elements, to list binary, ternary, and quaternary alloys. It would then be natural to explain, unless it was certain the intended readers already understood, what each of these terms means, what alloy elements are used, and what special qualities each one contributed to the steel. What we are talking about here is not peculiar to classification writing; it is the same old story of developing your facts and ideas sufficiently so that your reader can thoroughly understand you.

Make certain that in a subclassification you discuss characteristics peculiar to that one subclassifiaction only. It is the same as clarifying the subject but in this case you will point something significant about this particular kind and not something characteristic of any kind.

In the process of subdividing a subject, a point is reached at which no further subdivision is possible. At this point, one is dealing with varieties of a species.

A Note on Partition

Earlier we defined the term “partition”; now we will comment briefly on the use of partition in exposition. Classification, as we have seen, is a method of analysis ( and exposition) that deals with plural subjects. You can classify houses, for instance, by considering them from the point of view of architectural style, principal material of construction, number of rooms, and so on. But you cannot classify a house except in the sense of putting it into its proper place in a classification that deals with houses. You can analyze a particular house, however, by naming and discussing its parts: foundation, floors, walls, and so on. This analytical treatment of a single thing (idea, mechanism, situation, substance, function) is called “partition,” or simply “analysis.” As you know, it is a familiar and useful way of dealing with a subject. The seven classification rules that were discussed also apply to partitioning.
You don’t need to be urged to break down a subject for purposes of discussion. You would do it anyway, since it is a natural, almost inevitable, method of procedure. After all, a writer is forced into subdividing subject matter for discussion because of the impossibility of discussing a number of things simultaneously. What is emphasized is that logical and effective principles in carrying out such divisions should be followed.

Four techniques are of special importance in technical writing: definition, description of a mechanism, description of a process, and classification. These techniques are not types of reports and it is important to remember that these techniques usually appear in a single report. It would be exceptional to find an entire report, even a short one, containing only one of these techniques. For example, two or more techniques might be closely interwoven as a writer described the design, construction, and operation of a mechanism. The intermingling of these techniques, however, does not alter the basic principles of their use. These techniques can be studied most effectively by taking one technique at a time.
The treatment of these techniques will stress the practical rather than the theoretical, particularly in the subjects on definition and classification.

In technology, words have precise, specific meanings; therefore there is a need for defining a technical term clearly. The extent to which a term should be defined or the length of a definition depends on the writer’s purpose and the knowledge level of the reader.
Before going to the problem of “how to define”, it is better to “think about what should be defined first.” It is not possible of course, to set up an absolute list of terms and ideas that would require definition, not even for a specific body of readers, but it is possible and desirable to clarify the point of view from which the problem of definition should be attacked.
The relationships of words to the ideas and things for which they stand can become very complex. However, there is a simple and helpful way of classifying words, as they will appear to your reader. The words will fall into one of the following categories:

1. Familiar words for Familiar things. The only observation that need be made about the first category is that familiar words for familiar things are fine; they should be used whenever possible. To the extent that they can be used, definition is unnecessary. Nothing is ever gained by using, just for the impressiveness, words that may puzzle the reader.

2. Familiar words for unfamiliar things. The words in this second category present a rather special problem to the technical writer. These are the everyday, simple words that have special meanings in science and technology. Most of them may be classed as “shop talk,” or language characteristic of a given occupation. Because they are a part (often a very colorful part) of the language of a specialized field, it is easy to forget that they may not be a part of the vocabulary of the reader, at any rate not in the special sense in which they are used. Consider a term like “quench”. Everyone knows this word in the familiar sense, but not everyone knows that in the metallurgical sense it means the dipping of heated steel into water, oil, or other bath, to impart necessary hardness.
Every field of engineering and science has a great many of these simple words that have been given specialized meanings.
Examine the following list:

Bastard – A course-cut file but not as rough as a first-cut.
Bite – Trade term for etching on metal plate.
Bed – The part of the lathe which supports the headstock, tailstock, and carriage.
Doctor – Local term for an adjuster or adapter that allows chucks from one lathe to be used on another. The term “dutchman” is sometimes used in this way.
Dog – The carrier of a lathe. One of the jaws of the chuck.
Land – Space between flutes or grooves in drill, taps, reamers,
and other tools.
Nose – The business end of tools or things. The threaded end of a lathe or milling-machine spindle, or the end of a hog-nose drill or similar tool.
Cheater – An extension on a pipe wrench.
Dirty – To make ink darker.

The reader may not confuse the everyday meaning of such terms with the technical sense they have in a particular report, but there is not much doubt that when encountering a term of this sort, the reader, unless a specialist in the field being discussed, will initially wrongly identify the word according to its everyday meaning. In any event, the writer must be alert to the need for defining such terms.

3. Unfamiliar words for Familiar things. We condemned writers who prefer big and pretentious words for referents with which their readers are familiar. Such a practice should always be condemned if a simple, familiar term exists which means the same thing. But an unfamiliar word for a familiar thing may be used if there does not exist any simple, familiar term for it. Both convenience and accuracy justify it. Suppose an electrical engineer was writing about special tactical electronic equipment making use of direct wave transmission. It is not likely that he would be satisfied to use the phrase “short wave” when dealing specifically with, say, the 300- to 3000- megacycle band. A more precise phrase is “ultrahigh frequency” (UHF). Your solution is simple: you use the convenient term but you define it.
You will have to judge whether your subject matter demands the use of such terms and whether they are familiar to your readers. If they are needed, or if they are justifiably convenient, and you decide that your readers do not know them, you should define them.

4. Unfamiliar words for unfamiliar things. This category embraces most of those words that are commonly thought of as “technical” terms. They are the specialized terms of professional groups; big, formidable looking (to the non-specialist), they are more often than not of Greek or Latin origin. Terms like “dielectric,” “hydrosol,” “impedance” are typical.

With these facts in mind about what to define, we can more intelligently consider the problem of how to define.

Methods of Definition

In so far as it is possible to use simple, familiar terminology, the problem of definition may be avoided entirely. In other words, the best solution to the problem of definition is to avoid the need for it. When it is necessary, however, there are two methods or techniques that may be employed. The first may be described as informal; the second, as formal. The second takes two forms: the sentence definition and the extended or amplified definition. Each of these techniques has its own special usefulness.

Informal

Essentially, informal definition is the substitution of a familiar word or phrase for the familiar term used. It is therefore a technique to be employed only when you are reasonably certain that it is the term alone and not the referent which is unfamiliar to the reader.
Instead of a single-word substitution, sometimes a phrase, clause, or even a sentence may be used in informal definition. Such kinds of definition have general facts and they are worthwhile to be noted and these are:

First, they are partial, not complete definitions. But such illustrations are enough in a discussion where thorough understanding of the terms is not necessary and the writer merely wants to identify the term with the reader’s experience.

Second, informal definitions are particularly adapted for use in the text of a discussion. Because of their brevity and informality, they can be fitted smoothly into a discussion without appearing to be serious interruptions.

Third, when the informal definition reaches sentence length, it may not be greatly different from the formal sentence definition. It lacks the emphasis, and usually the completeness however which may be required if a term defines an idea or a thing that is of critical importance in a discussion. In short, if one wants to make certain that the reader understands a term and that the term is important enough to focus special attention on it, he will find the formal sentence definition, and perhaps the amplified definition or article of definition, more effective.

Formal Sentence Definition

The informal definition does not require the application of an unchanging, rigid formula; rather, it is an “in other words” technique – the sort of thing we all do frequently in conversation to make ourselves clear. In formal definition, however, it is different. A logically dictated, equation-like statement is always called for, a statement composed of three principal parts for which there are universally accepted names. These are the species, the genus, and the differentia.

The species is the subject of the definition, or the term to be defined.

The genus is the family or class to which the species belongs.

The differentia is that part of the statement in which the particular species’ distinguishing traits, qualities, and so forth are pointed out so that it is set apart from the other species comprising the genus.

Species

= Genus

+ Differentia

Brazing

is a welding process

wherein the filler metal is a non-ferrous metal or alloy whose melting point is higher than 1000F but lower than that of the metals alloys to be joined.

The term – the word or phrase to be defined

The class or genus – the specie or family to which the term belongs

The differentia – that part of the definition which states the distinctive characteristics of the term which distinguishes it from other members of the same class.

Defined as a process, then, formal definition involves two steps:

1. Identifying the species as a member of a family or class
2. Differentiating the species from other members of the same class.

The first step in the process of formal definition is that of identifying a thing as a member of a genus, or class. It is important to choose a genus that will limit the meaning of the species and give as much information as possible. In other words, the genus should be made to do its share of the work of defining. It wouldn’t help much, for instance, if a micrometer caliper is a “thing” or “device.” Generally speaking, the more informative the genus is made, the less one will have to say in the differentia. The more specific one can be in the genus, the less he has to say in the differentia.

Care must be taken in carrying out the second step of the process of formulating a sentence definition. Here the important point is to see that the differentia actually differentiates – singles out the specific differences of the species. A statement which attempts to differentiate a species must be examined critically to see if the definition is applicable solely to the species that is defined. If the statement is true of something else, it may be sure that the differentia is not sufficiently precise. One way to test a statement is to turn it around and see whether the species is the only term described by the genus and differentia.
Example:
“A C-shaped gauge in which the gap between the measuring faces is minutely adjustable by means of a screw whose end forms one face is a .” “Micrometer caliper” fills the blank, and if the definition is correct, it is the only term that accurately fills the blank. An accurate limiting genus coupled with a precisely accurate differentia will always ensure a good definition.

Practice in the writing of such formal definitions is good mental discipline as well as excellent training in conciseness and care in the use of words. However, extreme care must be taken in order to guard against certain faults that can impair their usefulness. Here are some pointers which must be followed when formulating formal definitions:

1. Define a word in simpler and more familiar terms. The purpose of definition is to clarify, not to confuse. A definition more difficult than the term being defined is useless.

ex:
Not this : An emulsion is a fluid consisting of a microscopically heterogeneous mixture of two normally immiscible liquid phases, in which one liquid forms minute droplets suspended in the other liquid.
Better: An emulsion is a fluid consisting of two microscopically different liquids which are insoluble with each other, wherein, one liquid forms very tiny droplets suspended in the other liquid.

2. Practice grammatical parallelism when defining a term. If the term is a noun, a gerund, or an infinitive, the class should be the same. Avoid defining with “is when,” “is where,” and “is what.” Is, being a linking verb, must be followed by the same type of construction that precedes it and an adverb clause cannot serve as a predicate nominative.

ex:
Not this: To oscillate is moving in a regular manner from side to side or back and forth.
Better: To oscillate is to move in a regular manner from side to side or back and forth.

3. Avoid circular definition which means the explanation of a term using the word itself or any of the derivatives. Nothing is achieved when a term is defined by mere repetition.

ex :
Not this : Engineering is the art and sciences taken up by persons to become engineers.
Better: Engineering is the professional art of directing the great sources of power in nature (matter and energy) for the benefit of man.

4. Do not put the term to be defined in too broad or too narrow a class.

ex :
Too broad: A riffle is a weapon . . . (knives, ice picks, swords, etc. are also weapons.)
Too narrow: A rifle is a gun . . . (pistols, revolvers, etc. are also guns)
Better: A riffle is a firearm with spiral grooves inside its barrel to impart rotary motion to its projectile or bullet and thus render its flight more accurate.

The extended definition is developed using any or a combination of the following methods:

1. Details
A term can be clarified by the addition of related or supporting particulars. To define a mechanism, a vivid description of its various parts will enable the reader to “see” it.

2. examples of instances
General statements particularly abstract definitions are made more concrete when illustrations are cited.

3. analogy, contrast or comparison
Analogy cites similarities. The reader is made to understand an unfamiliar object or idea by comparing it with another object or idea more familiar to the reader. Using contrast, the differences of both objects are cited in order to make the idea clear. Comparison combines the two methods of analogy and contrast (pointing out similarities and differences).

4. word derivation
Extended definitions may be revealing and interesting because they explain the origin of the term or the idea. Definitions such as these are seldom logically adequate but they are often extremely useful illustrations for clarification.

The one sentence definition usually serves as the topic sentence in an extended, amplified, or expanded definition.

Analogy

The human eye is the organ of sight or vision. Its parts are very similar to the parts of the camera. The zone sensible to light in the eye is called the retina and in the camera, the photographic film. The body of the eye and the camera is called the darkroom. The glass in our eye is the lens which focuses the image. The adjustable hole; for the lighting the eye is called the iris and in the camera, the diaphragm. Besides these structural characteristics, the eye, like the camera, receives the images from the outside world in an inverted position.

Contrast

A laser is a powerful beam of coherent light, the rays of which stay parallel over vast distances. The laser light beam is entirely different from the beam produced by all other light sources. In the first place, the ideal laser beam consists of light on a single wavelength. A beam of light from other sources contains a range of colors and is not concentrated in one specific color. The second difference between a laser beam and an ordinary light beam is that the light waves that form the laser beam are all in phase; that is, the crests of the waves all occur together. This kind of light is called coherent light. Other light sources generate waves that are out of phase with each other. As a result, troughs may occur at the same time as crests, producing a much less powerful beam. Such a beam diverges if some form of focusing is not used. An ideal laser beam, however, will not diverge.

Comparison

There are two measuring devices which are both used to measure short distances accurately, the vernier caliper and the micrometer caliper. The vernier caliper is a semiprecision-measuring tool used to measure short distances accurately to hundredths of a centimeter, whereas the micrometer caliper is a precision measuring instrument used to measure very short distances accurately to thousandths of a centimeter. Both the vernier and the micrometer calipers have two scales. The vernier caliper has the fixed scale and the sliding or the vernier scale. In the Metric System, the fixed scale is calibrated in millimeters and the vernier scale in tenths of a millimeter. If the fixed scale reads 2 centimeters and 3 millimeters, this means 0.07 cm. Adding the two readings 2.3 + 0.07 = 2.37 – the actual reading. The two scales of the micrometer caliper are the horizontal and the vertical. The horizontal gives the readings in hundredths of millimeters or thousandths of a centimeter. The actual reading is equal to the sum of the readings which will be in thousandths of a centimeter. While the vernier caliper can be calibrated in both the Metric and English systems, the micrometer caliper can be calibrated in the Metric system only.

Word Derivation

Geometry is a very old science. The word geometry is derived from the two Greek words, geos meaning “earth” and metron meaning,”measure”; hence literally, geometry means “earth measure.” It is supposed to have had its beginning with the land surveying by the priests of Egypt. The Nile River periodically overflowed its banks carrying away landmarks in its valley, and by altering its course, increased or decreased the taxable value of the adjoining lands. This necessitated frequent measurements to re-establish vanishing landmarks and to determine not only the position of property but also its extent. Recognizing the merits of having a system in such a branch of knowledge, the Greeks sought to transform and develop the art of mensuration which they learned from the Egyptians into a science. At present, the word geometry has a broader and deeper meaning than it had when it was first adopted. It is that branch of mathematics which deals with the relations among and measurements of lines, angles, surfaces, and solids. .

A process is a series of actions, and fundamentally the description of a process is the description of action. The action may be either one of two types. One type is that in which attention is focused on the performance of a human being, or possibly a group of human beings. A simple example is filing a workpiece by hand; in a description of this process, emphasis would fall naturally upon the human skills required. The other type involves action in which a human operator either is not directly concerned at all, or inconspicuous. An instance is the functioning of a contactor.
In describing almost any process, regardless of types there are problems that usually arises and these are:
1. adaptation of the description to the reader
2. overall organization
3. use of illustrations

Adapting the description to the reader depends, as always, upon an analysis of the reader’s needs. As in the description of a mechanism, if the reader wishes to use the description as a practical guide, it becomes necessary for the writer to give careful attention to every detail. If the reader is interested only in acquiring a general knowledge of the principles involved and has no intention of trying to perform the process or to direct its performance, the writer should avoid many of the details and emphasize the broad outlines of the process.
The fundamental organization of a process description is simple, consisting merely of an introduction followed by a description of each step in the process in the order in which they occur. But this simplicity is usually marred by the necessity of discussing the equipment and the materials used.
There are basically two ways of incorporating the discussion of equipment and materials into the description as a whole. One is to lump it all together in a section near the beginning; the other is to introduce each piece of equipment and each bit of material as it happens to come up in the explanation of the steps in the process. The advantage of confining the description of equipment and materials to a single section near the beginning is that such discussion does not then interrupt the steps in the action itself. This method is usually practical if the equipment and materials are not numerous. If they happen to be so numerous or so complex that the reader might have difficulty in remembering them, the other method of taking them up as they appear in the process is preferable. The second method is by far the more common.

PART I OPERATOR TAKES A CONSPICUOUS PART

In the description wherein the operator takes a conspicuous part, still the description is divided into; introduction, step-by-step description, and conclusion.

A. The introduction
The introduction of the description of a process is a comprehensive answer to the question, “What are you doing?” An answer to the question can be given by answering still other questions, principally the following:

What is this process?

Who performs this process?

Why is this process performed?

What are chief steps in this process?

From what point of view is this process going to be considered in this discussion?

Why is this process being described?

It is not always necessary to answer all six questions, and it is not necessary to answer them in the order in which they happen to be listed. It will be helpful to consider each question in turn to get some notion of what is needed to be done.

1. What is this process?
Early in the report readers must be told enough about what the process is, so that, they can grasp the general idea. The way in which this explanation is given depends upon how much the readers are presumed to know about the process, as well as upon the nature of the process itself. “What is this process?” is simply a problem of definition, and therefore the use of comparison and of generalized description is often particularly helpful.

2. Who performs this process?
Very often the statement about who performs the process will appear as a natural or necessary element in some other part of the introduction. Often no statement is required.

3. Why is this process performed?
It is absolutely necessary that the reader know why the process is performed – what its purpose is. Sometimes simply explaining what the process is, or defining it, makes the purpose
clear. Sometimes, however, the purpose of a process may not be clear from a statement of what it is or how it is performed. Then it is necessary to be quite explicit in stating its complete purpose.

4. What are the chief steps in this process?
The listing of the chief steps in the process is an important part of the introduction. It is important because it helps the reader understand the process before the details of its execution are presented. Even more important is its function in telling the reader what to expect in the material that follows. It is a transitional device. It prepares the reader for what lies ahead. The list of steps may appear as a formal list, with a number or letter standing beside each step. If this method seems too mechanical, the steps may be stated in ordinary sentence form, with or without numbers or letters. The steps should be discussed in the order in which they are listed.

5. From what point of view is this process to be discussed? Why is this process being described?
The latter question calls for a specific statement of purpose – the purpose of including the description of this process in the report of which it is a part. In other words, readers will want to know why you are asking them to take time to read your description of the process. Be careful to keep in mind the distinction between the purpose you have in writing about it. These are very different matters. The first of the two questions is likewise related to the matter of purpose, but here the interest is not in why the process is being described; rather it is in why it is being described in a particular way or from a given point of view.

The chief steps

Organization

With the possible exception of the discussion of equipment and materials, the introduction to a description is followed directly by a description of the chief steps in the process. Two problems appear in organizing the description of the chief steps.
One is how to organize the steps; the other is how to organize the material within each individual step.
The organization of the steps can be dismissed at once for it is chronological in order. The organization within the description of the individual steps requires more discussion. It is because, each individual step constitutes a process in itself. The individual step should therefore be introduced properly, and if necessary, divided into substeps. Its description is essentially a miniature of the description of the process as a whole.

Description of the action

In describing the action, the writer must say everything the readers need to know to understand, perhaps even to visualize the process. The omission of a slight detail may be enough to spoil everything. Care should be taken not only in connection with the details of what is done, but also of how it is done. The content of the description of a process is governed by the reader’s need to comprehend every step in the action.

Style

What constitutes style in writing is very well discussed in the last semester of the study in TC. A discussion in style in the description of a mechanism however would focus on the problem of choice of the mood and voice of the predicate, and of the noun or pronoun used as a subject. A good many possibilities exist, but three are of special importance: the active voice and indicative mood, the passive voice and indicative mood, and the active voice and imperative mood.
Active Voice, Indicative Mood:
The next step is the application of the solder to the joint. This step requires the use of only the heated iron (or copper), and a length of the rosin-core solder. The solderer takes the iron in one hand and the solderer in the other, and holds the iron steadily against the wire joint for a moment to heat the wire. Then he or she presses the solder lightly against the joint, letting enough of it melt and flow over the wire to form a coating about the entire joint.
Passive Voice, Indicative Mood:
The next step is the application of the solder to the joint. This step requires the use of only the heated iron, and a length of the rosin-core solder. The iron is held steadily against the wire joint for a moment to heat the wire. Then the solder is pressed lightly against the joint until enough of it has melted and flowed over the wire to form a coating about the entire joint.
Active Voice, Imperative Mood:
The next step is the application of the solder to the joint. This step requires the use of only the heated iron, and a length of the resin-core solder. Take the iron in one hand and the solder in the other, and hold the iron steadily against the wire joint for a moment to heat the wire. Now press the solder lightly against the joint. Let enough of it melt and flow over the wire to form a coating about the entire joint.

The essential differences among these three ways can be expressed as the differences in the following three statements:
1. The solderer holds the iron.
2. The iron is held.
3. Hold the iron.
The effectiveness of the three depends upon several factors.
The advantage of the first way, the active voice and indicative mood, is that it gives the reader the greatest possible assistance in visualizing the action. It is the most dramatic. It comes as close as it is possible to come in words to the actual observation of someone performing the action. The presence of the person carrying out the process is kept steadily in the mind of the reader. This technique is without question a very effective one, and its possibilities should not be overlooked. Probably its best use occurs when the following three conditions prevail:

1. The process being described is one that is performed by one person.
2. The description is intended as general information rather than as a guide for immediate action.
3. The description is directed to readers who know little about the process.

The disadvantage of using the active voice is that it is likely to become monotonous unless handled with considerable skill. The monotony arises from the repetition of such terms as “the solderer,” “the operator,” or whatever the person performing the action is called, even though pronouns can be used to vary the pattern a little.
The advantage of the passive voice is that there is no problem about handling this hypothetical operator. The disadvantage is that the positiveness and aid to visualization of the active voice are missing. For a process performed by one person, or perhaps even a few persons, a combination of the active and the passive voices is possibly a good compromise.
The advantages of the third way, the active voice and the imperative mood, are that it is concise, easy to write, and a reasonably satisfactory guide for immediate action, as long as the process is not too complex. It is however, not really a description at all; it is a set of directions, there is likely to be a slighting of emphasis upon purpose, and a consequent weakness of the report as an explanation of the process. The imperative mood promotes action better than it promotes understanding.
There are numerous possibilities in addition to the three just illustrated. The practical possibilities can be listed as follows: ex.

All in all, the three forms (active indicative, passive indicative, and active imperative) are by far the most useful. These remarks refer only to the type of process in which there is a conspicuous operator.
The last part of the description of the process is naturally the conclusion. It is not always necessary to write a formal conclusion. Whether one is desirable depends, of course, on whether it will help the reader. Sometimes the reader needs help in matters like the following:
1. Fixing the chief steps in mind (listing them again might help)
2. Recalling special points about equipment or materials
3. Analyzing the advantages and disadvantages of the process.
4. Noting how this process is related to the other processes, or other work that is being done, or reported on

Analysis of the entire communication situation is necessary to determine whether a conclusion is desirable.

PART II OPERATOR DOES NOT TAKE A CONSPICUOUS PART.

The next is the process in which the human agent is less conspicuous. Such processes may be of great magnitude. They are distinguished by the fact that little emphasis falls directly upon the performance of a human being or beings. How does a transformer works? An answer to this question would be the description of a process; but in that description there would be little need to mention the quality of the performance of the operator.
All that needs to be considered is how the description of a process in which the operator does not take a conspicuous part differs from one in which the operator is important. The essential differences are three:

1. Emphasis is altogether on the action – on what happens – and not on the operator and how the operator performs certain actions.

2. The presentation is usually (not always) in the indicative, the passive indicative, or a combination of the two. The imperative mood never appears.

3. The terms “equipment” and “material” take on a somewhat different meaning and significance.

The three points just mentioned about the process in which the performer is not conspicuous rests on the same principles as in the first process wherein the operator is conspicuous. The main difference is that in the process wherein the operator is inconspicuous the imperative mood is never used obviously, because the emphasis falls on the action and not on the performer, that is why the term “materials and equipments” takes a different meaning because it is now the performer of the action.

A mechanism is generally defined as any object or system that has a working part or parts. Most often the term suggests tools, instruments, and machines. But other examples of mechanisms could be the human body and systems like the universe or a city, which is composed of parts that work together like parts of a machine. A technical man constantly works with mechanisms and always needs to understand them; what they do, what they look like, what parts they have, and how these parts work together.
There are three fundamental divisions of the description and these are the introduction, the part-by-part description, and the conclusion.
Because the description of a mechanism seldom constitutes an article or report by itself, the introduction required is usually rather simple. The two elements that need most careful attention are:
1. the initial presentation of the mechanism
2. the organization of the description

The Initial Presentation

At the beginning of a discussion of an unfamiliar mechanism, a reader immediately needs three kinds of information: what it is, what its purpose is, and what it looks like.

Organization of the description. It is possible to divide almost every mechanism into parts. In the initial presentation of the description, the purpose indicates the organization of the discussion that is to follow. Since it is logical to describe the principal parts one at a time, a list of the principal parts in the order in which one wishes to discuss them is a clear indication of the organization of the remainder of the description. The order in which the parts are taken up will normally be determined by either their physical arrangement or their function.

The list of the principal parts should be in parallel form.

The parts are usually named in normal sentence form, like,
“The principal parts of the lathe are (1) the bed, (2) the headstock, (3) the tailstock, and (4) the carriage.” But if the parts are numerous, it may be preferable to present them in the form of a list.

Part-by-Part Description

After the introduction and the mechanism logically divided into parts, the description of the first part follows. But the fact is that now, as far as method goes, it is almost as if one had not written a line. The part that is to be discussed is a brand new mechanism. The reader wants to know what it is. So again, it has to be introduced.
The lathe machine has been divided into the bed, the headstock, the tailstock and the carriage and now we are about to describe the bed. The first problem is to tell the reader what the bed is. The general procedure will be – as before – to define the part, to state its purpose, to indicate its general appearance, and finally, if necessary, to divide it into subparts.
What is done to the principal parts is also done to the subparts. In other words, the mechanism as a whole is progressively broken down into smaller and smaller units until common sense says it is time to stop. Then, each of these units is described in detail. The value of this system is for general policy, it is simply not true that all description should be handled in this way. Sometimes, for example, instead of giving a preliminary statement of all the subparts that will be described in a given section of the description, it is desirable not to mention a certain minor subpart at all except when it is actually described.
Aspects of the mechanism that needs careful attention when describing in detail a subpart of the mechanism:

Each of these matters need not be labored over mechanically, in the order stated, in every description. Which one needs attention, and what kind of attention, depends upon the reader and the subject. The same line of reasoning can be applied throughout the description. There is no formula that will fit every situation. The important thing is to decide what information the reader needs, and to provide it as clearly as possible.

Conclusion of the Description

The last principal function of the description of a mechanism is to let the reader know how it works, or how it is used, if this has not been done in the general introduction. Emphasis should naturally fall upon the action of the parts in relation to one another. This part of the writing constitutes in effect a description of a process usually highly condensed, and this will be discussed elaborately in the next technique of development.

Summary of the Principles of Organization
Description of a Mechanism
I. Introduction
A. What the mechanism is
B. Purpose
C. General appearance
D. Division into principal parts II. Part-by-part description
A. Part number 1
1. What the part is
2. Purpose
3. Appearance
4. Division into subparts
a. Subpart number 1
(1) What the subpart is
(2) Purpose
(3) Appearance
(4) Detailed description
(a) Shape
(b) Size
(c) Relationship to other parts
(d) Methods of attachment
(e) Material
(f) Finish
b, c, etc.- same as “a”
B, C, etc. – same as “A”

1. Always have in mind a specific reader, real or imaginary, when writing a report; and always
assume that this reader is intelligent, but uninformed.
2. Before you start to write, always decide what the exact purpose of your report is, and make sure that every paragraph, every sentence, every word, makes a clear contribution to that purpose, and makes it at the right time.
3. Use language that is simple, concrete, and familiar.
4. At the beginning and end of every section of your report check your writing according to this principles: “First you tell your readers what you are going to tell them, and then you tell them what have told them.”
5. Make your report attractive to look at.